Highway oil consumption (4 Viewers)

[richmondbob]

1997 80-series @ 368,573 miles

Driving Vancouver, BC to Edmonton, AB. Did first half yesterday, lots of uphill and heavy driving on passing lanes. Oil reads low (L on dipstick) after letting engine cool off for 10+ minutes. I've got 1 litre with me to add.

Is this normal?

Going to stop in at next Lordco to get more oil.

EDIT 2025-08-25 info on my 80:
- Shell Rotella 15w40
- over 368,xxx miles on original motor (that's over 592,xxx kms )
- no evidence of head gasket failure
- no blue smoke at tailpipe
- New PCV, EGR, EGR module and VSV
- Front cat removed and new rear cat installed (O2 sensors run fine)

 

[Devils Paw 80]

1997 80-series @ 368,573 miles

Driving Vancouver, BC to Edmonton, AB. Did first half yesterday, lots of uphill and heavy driving on passing lanes. Oil reads low (L on dipstick) after letting engine cool off for 10+ minutes. I've got 1 litre with me to add.

Is this normal?

Going to stop in at next Lordco to get more oil.

So that's about 700 miles, and your oil was definitely at the full line when you started? These beasts do have a tendency to burn oil, and yours is high miles.
However, 1 quart in that distance does seem a bit excessive. You can direct the service station attendant to "check the gas and fill the oil please".

 

[Fj80oregon]

If you don’t know the exact level when you started than it’s hard to determine if you have an issue. I would get it topped up and monitor after 500 miles. Many have posted around a quart of usage every 1000-1500 miles on higher mileage motors.

 

[LongDuck]

How fast were you trying to go? It matters. These things burn oil the faster you try to push it; the sweet spot seems to be about 60mph. Any faster than that, and I'd expect higher oil consumption, and I'm on a fresh short-block rebuild with 25k miles, rebuilt head and fresh spark plug seals.

(*Please reply in mph vs. kph - as I don't speak metric system.)

 

[robnicko]

If the original HG and associated seals etc then sounds normal, also what grade / type oil do you use?
mine did similar prior to the HG going and after re doing it uses nothing, just a leak at the oil pump housing which i keep putting off doing.....

 

[Devils Paw 80]

How fast were you trying to go? It matters. These things burn oil the faster you try to push it; the sweet spot seems to be about 60mph. Any faster than that, and I'd expect higher oil consumption, and I'm on a fresh short-block rebuild with 25k miles, rebuilt head and fresh spark plug seals.

(*Please reply in mph vs. kph - as I don't speak metric system.)

How much oil does yours burn?

 

[BTLSHP]

Post in thread 'Help burning oil driving cross Nebraska'

Aug 11, 2025

Correcting link to my thread below.



So, I have little new to offer. She is in the midst of climbing season a traveling most weekends. At 100 miles in on the Chevron XSP 400 15W-40 the dipstick read full. But it needs 500 or so and a longer trip. When we handed her the keys my ad says the car comes with a "mother in law" and like many she does a good job of avoiding me.

One thing the trip taught us was the altitude change exposed a weak cooling fan clutch and the temps of the engine...

• BTLSHP

• 

I think ours was burning oil most heavily when we got into rolling hills in Colorado.

We are still watching things, PCV and EGR seem fine. The new owner, my daughter, has 250 miles on it post oil change to 15w-40 dipstick reads full.

 

[LongDuck]

I run 20w50 Castrol since engine rebuild (*I live in the desert) and took the truck on a 1,300 mile trip from PHX to SD and had to empty the oil catch can every ~500 miles - every other fill up - back into the oil filler at the valve cover. I drove ~70mph the whole way and had about 1/2 quart of oil loss at the other end to top off to full on the dipstick, where I started.

Return trip, same mileage, same driving style, same oil volume burned. Prior to the engine rebuild and new seals, it was burning about 1/2 quart about every 1,000 miles - about every 4 fill ups, city driving, occasional highway driving.

High speed highway driving is what accelerates oil consumption,

 

[BTLSHP]

I run 20w50 Castrol since engine rebuild (*I live in the desert) and took the truck on a 1,300 mile trip from PHX to SD and had to empty the oil catch can every ~500 miles - every other fill up - back into the oil filler at the valve cover. I drove ~70mph the whole way and had about 1/2 quart of oil loss at the other end to top off to full on the dipstick, where I started.

Return trip, same mileage, same driving style, same oil volume burned. Prior to the engine rebuild and new seals, it was burning about 1/2 quart about every 1,000 miles - about every 4 fill ups, city driving, occasional highway driving.

High speed highway driving is what accelerates oil consumption,

Ok forgive the naivety of this question, what I am hearing you say is that the mechanism of burning this oil is up through the PCV valve into the intake manifold? I am only asking because I am thinking of the cleaning i did this last year.

 

[jpoole]

1FZFE, 330k miles roughly, often drive 75-80 on interstate and on other trips tow a 3k lb trailer (stay around or under 70 then). Run Rotella 15w40. Have never added oil between oil changes (6k mile intervals) in close to 100k miles of driving. No noticeable oil consumption.

On my rig, changing the valve stem seals and addressing most/sizeable oil leaks right after purchase was a big factor in no noticeable oil consumption.

I started running a catch can about 50k miles ago and have been collecting all of it's collections in a single jar. I'm up to about 12 ounces collected and it's clearly a mix of oil and condensation though I'm not sure on the ratios of one to the other, likely a little more oil than water.

 

[BTLSHP]

1FZFE, 330k miles roughly, often drive 75-80 on interstate and on other trips tow a 3k lb trailer (stay around or under 70 then). Run Rotella 15w40. Have never added oil between oil changes (6k mile intervals) in close to 100k miles of driving. No noticeable oil consumption.

On my rig, changing the valve stem seals and addressing most/sizeable oil leaks right after purchase was a big factor in no noticeable oil consumption.

I started running a catch can about 50k miles ago and have been collecting all of it's collections in a single jar. I'm up to about 12 ounces collected and it's clearly a mix of oil and condensation though I'm not sure on the ratios of one to the other, likely a little more oil than water.

Did you do the valve stem seals with a HG job? Or did you do them with the head on?

 

[jpoole]

With HG as PM work.

When purchased, my 80 was a mess with a cruddy cooling system, missing drive-train parts, bald/mismatched tires, moldy interior, etc. but it was cheap enough that I limped it home and immediately jumped into the typical bucket list of PM that you'll see thrown around on mud. The rusty sludge in the cooling system is the main reason that I pulled the head vs just running it. I feared that it had been overheated and then filled with water and "stop leak" before I bought it. Fortunately things looked good in the cylinders/etc. and it's done great in the 100k miles since the HG work, coolant flushes, etc. etc.

I'm surprised it doesn't use oil but I still check the oil regularly as I expect it to start using oil before too long. It's the best running engine that I've had experience with @ 330k miles and it gives no obvious indication of needing a rebuild at this point though I do wonder if it's lost power since new as hills at highway speeds could be easier.

 

[richmondbob]

So that's about 700 miles, and your oil was definitely at the full line when you started? These beasts do have a tendency to burn oil, and yours is high miles.
However, 1 quart in that distance does seem a bit excessive. You can direct the service station attendant to "check the gas and fill the oil please".

Oil was full and my foot was heavy on the gas

 

[BTLSHP]

Ours is in good basic condition. Literally bought by my dad after he retired to get to an from his weekend cabin year round and otherwise garaged. Compression is good, plugs have no sign of oil fouling.

240k miles an I am inclined to keep a couple of quarts of oil in it an run it until other issues dictate a HG. I have done much of the while you are in there work. Cooling system has been refreshed.

 

[richmondbob]

If you don’t know the exact level when you started than it’s hard to determine if you have an issue. I would get it topped up and monitor after 500 miles. Many have posted around a quart of usage every 1000-1500 miles on higher mileage motors.

Oil was full. On my drives BC to CA it wasn't unusual for me to need to top the oil up after driving on those 70mph/80mph highways.

 

[richmondbob]

How fast were you trying to go? It matters. These things burn oil the faster you try to push it; the sweet spot seems to be about 60mph. Any faster than that, and I'd expect higher oil consumption, and I'm on a fresh short-block rebuild with 25k miles, rebuilt head and fresh spark plug seals.

(*Please reply in mph vs. kph - as I don't speak metric system.)

I'm gonna reserve my right to not incriminate myself but let's just say Ricky Bobby would be proud.

 

[richmondbob]

If the original HG and associated seals etc then sounds normal, also what grade / type oil do you use?
mine did similar prior to the HG going and after re doing it uses nothing, just a leak at the oil pump housing which i keep putting off doing.....

Shell Rotella15w40

 

[richmondbob]

Post in thread 'Help burning oil driving cross Nebraska'

Aug 11, 2025

Correcting link to my thread below.



So, I have little new to offer. She is in the midst of climbing season a traveling most weekends. At 100 miles in on the Chevron XSP 400 15W-40 the dipstick read full. But it needs 500 or so and a longer trip. When we handed her the keys my ad says the car comes with a "mother in law" and like many she does a good job of avoiding me.

One thing the trip taught us was the altitude change exposed a weak cooling fan clutch and the temps of the engine...

• BTLSHP

• 

I think ours was burning oil most heavily when we got into rolling hills in Colorado.

We are still watching things, PCV and EGR seem fine. The new owner, my daughter, has 250 miles on it post oil change to 15w-40 dipstick reads full.

Hills and speed seem to be why my 80's been burning the oil. Going to edit my post to give the oil and maintenance info.

 

[richmondbob]

I run 20w50 Castrol since engine rebuild (*I live in the desert) and took the truck on a 1,300 mile trip from PHX to SD and had to empty the oil catch can every ~500 miles - every other fill up - back into the oil filler at the valve cover. I drove ~70mph the whole way and had about 1/2 quart of oil loss at the other end to top off to full on the dipstick, where I started.

Return trip, same mileage, same driving style, same oil volume burned. Prior to the engine rebuild and new seals, it was burning about 1/2 quart about every 1,000 miles - about every 4 fill ups, city driving, occasional highway driving.

High speed highway driving is what accelerates oil consumption,

Recalling my BC to CA runs, I can agree on speed being a factor.